Studies Clash on GLP-1 Agonist Risks

The conflicting data on GLP-1 agonists extends to the cellular level; some preclinical studies suggest these drugs may promote the formation of bone-building osteoblasts while inhibiting osteoclasts, which break down bone tissue. This dual action could theoretically mitigate bone loss associated with rapid weight reduction. However, the precise mechanisms and long-term clinical impact on fracture risk remain unclear. One retrospective cohort study presented at the 2026 American Academy of Orthopaedic Surgeons (AAOS) annual meeting found a significantly increased five-year risk of osteoporosis, gout, and osteomalacia in patients with Type 2 diabetes and obesity using GLP-1 receptor agonists. The study, led by Muaaz Wajahahth from Michigan State University, reported a 1.29 times greater risk for osteoporosis and a 2.55 times greater risk for osteomalacia compared to non-users. Conversely, other research presented at the same AAOS meeting highlighted short-term benefits in surgical settings. A study led by Haroun Haque of SUNY Downstate College of Medicine found that GLP-1 agonist use was associated with significantly lower odds of postoperative emergency department visits and reduced surgical site infections in patients undergoing total knee and hip replacements. For patients with morbid obesity (BMI ≥ 40 kg/m2) undergoing total knee arthroplasty, the use of GLP-1 agonists for at least 90 days before and after surgery was linked to a significant decrease in 90-day rates of periprosthetic joint infections (1% vs. 1.8%) and readmissions (5.3% vs. 8.9%) compared to a control group. The concern over muscle health stems from the fact that the rapid weight loss induced by GLP-1 agonists affects both fat and lean mass. For older adults, who already face age-related muscle loss (sarcopenia), this could increase the risk of frailty, falls, and fractures. While some animal studies suggest GLP-1 agonists might have a muscle-preserving effect at low doses, clinical data in humans has shown a reduction in lean mass along with fat loss. The divergence in findings may be related to the duration of GLP-1 agonist use and the specific patient populations studied. Short-term use in a perioperative setting may offer anti-inflammatory and metabolic benefits that reduce immediate complications, while long-term exposure may lead to cumulative effects on bone and muscle metabolism that are not yet fully understood. Researchers emphasize that five- and 10-year follow-up data are only now becoming available, highlighting the need for more extensive, long-term clinical trials to definitively establish the safety and efficacy of these drugs on musculoskeletal health. Ongoing studies are examining the effects of newer GLP-1 agonists, like semaglutide, on bone mineral density and fracture incidence to provide clearer guidance for clinicians.